In the real world they don’t tell you what to do every minute of the day. You are responsible for your own yiras shomaim and limud.
Also at home a bachur has more responsibility if he helps in house chores. He needs to be parent with his sibling’s. In the yeshiva sometimes you can get everything.
There are exceptions to both paragraph. Some yeshivot give guys total freedom. Some bachurim have much more responsibility at the yeshiva.